\begin{tikzcd}[column sep=small, row sep=small]
R \arrow[r, hook] \arrow[d, hook] & Z \arrow[d, hook] \\
T \arrow[r, hook] & G \arrow[d] \\
& \Gamma
\end{tikzcd}

\begin{tikzcd}
G \arrow[r, "\text{épim}"] & H \\
G^{\circ}_{\mathrm{réd}} \arrow[u, no head] \arrow[r, no head] & H^{\circ} \arrow[u]
\end{tikzcd}

\begin{tikzcd}
\mathrm{Pic}(G/B) \arrow[r, leftrightarrow] \arrow[d, no head, "\wr"'] & \mathbf{D}(T/R) \arrow[d] \\
\mathrm{Pic}(G/B) & \mathbf{D}(T) \arrow[l]
\end{tikzcd}